Swinging on the Säckpipa

Posted in Jazz with tags , , on November 27, 2020 by telescoper

And now for something completely different.

This is Swedish musician Gunhild Carling out front of a swinging big band on the open-air stage at Central Park, New York, tearing it up on the bagpipes*.

You’re welcome.

 

 

(*to  be precise these are a kind of traditional Swedish bagpipes known as the säckpipa).

 

Cosmological Non-Linearities as an Effective Fluid

Posted in The Universe and Stuff with tags , , , , , , , on November 27, 2020 by telescoper

We know our Universe is inhomogeneous, comprising regions of high density (galaxies and clusters of galaxies) as well as regions of much lower density (e.g. cosmic voids). Our standard cosmological models are based on exact solutions of Einstein’s equations of general relativity that assume homogeneity and isotropy. The general assumption is that if we confine ourselves to large enough scales the effect of the clumpiness of matter can either be disregarded or treated using perturbation theory. As far as we can tell, that approach works reasonably well but we know it must fail on smaller scales where the structure is in the non-linear regiome where it can’t be described accurately using perturbation theory because the fluctuations are so large.

From time to time I’ve idly wondered whether it might be possible to treat the these non-linearities in general relativity by treating them as a kind of fluid with an energy-momentum tensor that acts as a correction to that of the perfect fluid form of the background cosmological model. This would have to be done via some sort of averaging so it would be an effective, coarse-grained description rather than an exact treatment. It is clear though that non-linearities would generate departures from the perfect fluid form, particularly resulting in off-diagonal terms in the energy-momentum tensor corresponding to anisotropic stresses (e.g. viscosity terms).

Anyway, a recent exchange on Twitter relating to a new paper that has just appeared revealed that far cleverer people than me had looked at this in quite a lot of detail a decade ago:

You can find the full paper here.

There are quite a lot of subtleties in this – how to do the spatial averaging, how to do the time-slicing, etc – which I don’t fully understand but at least I’m reassured that it isn’t a daft idea to try thinking of things this way!

P.S. The relativistic simulations reported in this paper could in principle be used to estimate the parameters mentioned in the abstract above, if that hasn’t been done before!

 

John & Diego

Posted in Poetry, The Universe and Stuff with tags , , on November 26, 2020 by telescoper

The Guardian obituary of John Barrow (written by Michael Rowan-Robinson) has finally appeared in today’s print edition*, alongside that of footballer Diego Maradona who passed away yesterday.

As a lifelong football fan I think John would have been amused by the coincidence, especially because John’s first book (co-written with Joe Silk) was called The Left Hand of Creation:

*I don’t usually buy foreign newspapers, but I managed to find a copy of today’s Grauniad in Maynooth.

Maynooth University Open Days!

Posted in Education, Maynooth with tags , , on November 26, 2020 by telescoper

It’s almost time once again for our autumn open days at Maynooth University. This autumn the two days are virtual events but also differ in that the first day is devoted to clubs, societies and other wider aspects of student life while the second is dedicated to information about the academic side, i.e. courses of study.

I’ve recorded some video material that will be used on the second day and I’m also going to be online on Saturday from 10am to 2pm to answer questions from prospective students. In order to experience these and other delights you have to register, which you can do here.

Here is a video tour of the Maynooth University campus, filmed in better weather!

You will see that it includes an artist’s impression of the new building on the North Campus which isn’t actually finished yet, but which is coming along nicely.

And here is a gratuitous picture of our star attraction:

Out of the REF

Posted in Biographical, Cardiff, Maynooth with tags , , , , on November 25, 2020 by telescoper

I was talking over Zoom with some former colleagues from the United Kingdom last week, and was surprised to learn that, despite the Covid-19 pandemic, the 2021 Research Excellence Framework is ploughing ahead next year, only slightly delayed. There’s no stopping bureaucratic juggernauts once they get going…

One of the major plusses of being in Ireland is that, outside the UK academic system, there is no REF. One can avoid the enormous workload and stress generated by this exercise in bean-counting My memories of the last REF in 2014 when I was Head of School at Sussex are quite painful, as it went badly for us then. I hope that the long-term investments we made then will pay off, though, and I hope things turn out better for Sussex this time especially for the Department of Physics & Astronomy for which the impact and environment components of the assessment dragged the overall score down.

The census period for the new REF is 1st August 2013 to 31st July 2020. Not being involved personally in the REF this time round I haven’t really paid much attention to the changes that have been adopted since 2014. One I knew about is that the rules make it harder for institutions to leave staff out of their REF return. Some universities played the system in 2014 by being very selective about whom they put in. Only staff with papers considered likely to be rated top-notch were submitted.

Having a quick glance at the documents I see two other significant differences.

One is that in 2014, with very few exceptions, all staff had to submit four research outputs (i.e. papers) to be graded. in 2021 the system is more flexible: the total number of outputs must equal 2.5 times the summed FTE (full-time equivalent) of the unit’s submitted staff, with no individual submitting more than 5 and none fewer than 1 (except in special cases related to Covid-19). Overall, then there will be fewer outputs than before, the multiplier of FTE being 2.5 (2021) instead of 4 (2014). There will still be a lot, of course, so the panels will have a great deal of reading to do. If that’s what they do with the papers. They’ll probably just look up citations…

The other difference relates to staff who have left an institution during the census period. In 2014 the institution to which a researcher moved got all the credit for the publications, while the institution they left got nothing. In 2021, institutions “may return the outputs of staff previously employed as eligible where the output was first made publicly available during the period of eligible employment, within the set number of outputs required.” I suppose this is to prevent the departure of a staff member causing too much damage to the institution they left.

I was wondering about this last point when chatting with friends the other day. I moved institutions twice during the relevant census period, from Sussex to Cardiff and then from Cardiff to Maynooth. In principle, therefore, both former employees could submit my outputs I published while I was there to the 2021 REF. I only published a dozen or so papers while I was at Sussex – the impact of being Head of School on my research productivity was considerable – and none of them are particularly highly cited so I don’t think that Sussex will want to submit any of them, but they could if they wanted to. They don’t have to ask my permission!

I doubt if Cardiff will be worried about my papers. Among other things they have a stack of gravitational wave papers that should all be 4*.

Anyway, thinking about the REF an amusing thought occurred to me about Research Assessment. My idea was to set up a sort of anti-REF (perhaps the Research Inferiority Framework) based not on the best outputs produced by an institutions researchers but on the worst. The institutions producing the highest number of inferior papers could receive financial penalties and get relegated in the league tables for encouraging staff to write too many papers that nobody ever reads or are just plain wrong. My guess is that papers published in Nature might figure even more prominently in this

Astrophysics & Cosmology Masterclass at Maynooth

Posted in Education, Maynooth, The Universe and Stuff with tags , , on November 24, 2020 by telescoper

Stealing the idea from our long-running Particle Physics Master Class (which sadly had to be cancelled this year for Covid-19 related reasons, but will resume in 2021), the Department of Theoretical Physics at Maynooth University has decided to launch a Masterclass in Astrophysics & Cosmology. The first one will be on January 14th 2021.

This will be a half-day virtual event via Zoom. It’s meant for school students in their 5th or 6th year of the Irish system, but there might be a few of them or their teachers who see this blog so I thought I’d share the news here. You can find more information, including instructions on how to book a place, here.

Here is the official poster and the programme:

I’ll be talking about cosmology early on, while John Regan will talk about black holes. After the coffee break one of our PhD students will talk about why they wanted to study astrophysics. Then I’ll say something about our degree programmes for those students who might be interested in studying astrophysics and/or cosmology as part of a science course. We’ll finish with questions either about the science or the study!

Four Weeks To Go

Posted in Biographical, Covid-19, Education, Maynooth with tags , , , , , on November 23, 2020 by telescoper

As I await another Zoom meeting I remembered this cartoon from last week’s Private Eye, which sums up the prevalent mood amongst academics these days (and no doubt people in other kinds of job too).

At the start of this morning’s Panopto lecture I realised that there are still 4 weeks left of this Semester before the Christmas break. I was a bit surprised by that as this term seems to have lasted a decade already. The time certainly hasn’t zoomed by. Still, at least I’ve more-or-less kept up with my planned schedule of lectures in both of my modules without slipping. I may even be able to finish lectures to my 2nd year Vector Calculus in time to do a bit of revision in the final week.

That’s not to say other things haven’t slipped. The greatly increased time for teaching needed to move everything online hasn’t left much time for research or anything else. I keep meaning to work in the evenings to deal with outstanding things but mostly I find once I’ve done the necessary admin and teaching stuff all I can do is sleep. It seems that I’ll have to work over Christmas to finish off the backlog. Given that I didn’t have a holiday this summer that’s not ideal, but it’s unlikely I’ll be going anywhere over the “festive” season owing to Coronavirus restrictions so I might as well make the best of it.

We don’t have much idea how things will work out next Semester. The politicians seem to be wanting universities to have more on-campus teaching in the New Year. They also want to end the current restrictions to end before Christmas. In fact the current regime is suppose to end on December 2nd, which is next week, and cases are still running around 400 per day. I don’t think they can do both of these and for the Covid-19 situation to remain under any semblance of control. I think the likeliest scenario is that cases surge over the next few weeks and the Christmas break and we have to go back into full restrictions in January or February.

There is however the prospect of a vaccine or vaccines being available fairly early next year so maybe the end of this is in sight. I really hope we can get back to campus normality at some point in 2021. I do feel very sad about the effect all these restrictions has been having on the students. It’s not just having to have remote lectures. I think having a lecturer in the same room is an advantage, but the loss of it is not the worst issue. We encourage our students to work with each other in their learning, and I’m sure students learn at least as much from each other as they do from the lecturer. Peer group learning is more difficult when your peers are sitting in separate locations most of the time.

Earlier today I found myself using the phrase “getting back to normal” in connection with plans for next teaching year. Then I realise that we staff know what we mean by “normal” but our first-year students don’t. I have a feeling that may might find it more difficult to adjust to the old normal than they did to the new one.

And in any case many of our students in all years did not take up accommodation in Maynooth at the start of this year because of the remote teaching. Even if we did on campus lectures or tutorials next term, I suspect many will stay at home anyway to avoid substantial cost of rented accommodation. We will therefore have to continue making material available online whatever happens.

Anyway, what may or may not happen next Semester is to a large extent out of my hands so I won’t be making any firm decisions on what approach I will be taking until much closer to the start of Semester 2 In the meantime the goal is to fight the exhaustion and try get through to the end of term in one piece.

Job Opportunities in Quantum Information Processing in Maynooth

Posted in Maynooth, The Universe and Stuff with tags , , , on November 23, 2020 by telescoper

Gratuitous Graphic purporting to represent Quantum Information Processing

Regular readers of this blog may recall an announcement that the Department of Theoretical Physics scored a notable success, or rather Dr Professor Jiri Vala did, in securing funding as part of a project called Quantum Computing in Ireland: A Software Platform for Multiple Qubit Technologies. To be eligible for this kind of funding, projects must involve businesses and this particular project includes IBM Ireland Ltd, MasterCard Ireland, Rockley Photonics and Equal 1 Laboratories, the latter two being SMEs based in the Dublin area. The project also involves the Tyndall National Institute (Cork); University College Dublin; and Maynooth University. This is the first large collaboration in Ireland in this area.

Well, now that the funds have actually arrived, I  thought I’d use the medium of this blog to pass on the information that the Department of Theoretical Physics at Maynooth University is looking two appoint not one but two theoretical physicists as postdoctoral researchers to work on this project.

The first position (for which you can find further details here) is  to work on modelling and simulations of quantum photonic systems for quantum information processing.

The second position (further details here) is to work on the evelopment of compilers, quantum control protocols and algorithms for quantum information processing in quantum photonic systems.

The deadline for both positions is Sunday 6th December 2020, so there’s not much time to apply!

Please feel free to pass this on to anyone you think may be interested!

 

On the GAA

Posted in Biographical, History, Sport with tags , , , , , on November 22, 2020 by telescoper

Since moving to Ireland almost three years ago I have (somewhat unexpectedly) become a fan of GAA and regularly watch both hurling and Gaelic football on the TV, which is quite often.

Ireland is very keen on sports generally, with big followings for both rugby and soccer but, at least in terms of attendances, hurling and Gaelic football are by far the most popular sports in Ireland. That’s quite remarkable because these are entirely amateur games. One of the great things about the GAA is that it’s a real grass roots organization, where even games between local clubs can attract very big crowds. (I’m talking about the pre-Covid era there, obviously.) The players tend to be local and there’s a strong involvement of the community in the local clubs.

Hurling is my favourite GAA sport – the level of skill on display is truly awesome and it’s played at an amazingly fast tempo – but I do watch the football when I can too and am more gradually getting into it. Incidentally, these two sports are played on the same pitches with the same goals and the same number of players on each side (15) and have basically the same rules – with a player’s hurley (stick) in hurling being in one-to-one correspondence as far as the rules are concerned with a player’s foot in Gaelic football. The ball of course is bigger in football; the small one used in hurling is called a sliotar. Scoring is the same in both: 1 point getting the ball between the two posts over the bar as in rugby and a goal (3 points) for getting the ball into the back of the net below the bar.

I took a break in the early afternoon yesterday to watch the All Ireland Quarter Final match in the hurling between Galway and Tipperary, an entertaining match played in fine weather which was won by Galway 3-23 to 2-24. Later on, I settled down to watch the Leinster provincial final between Dublin and Meath live from Croke Park in the evening. Given that this match was on the same day as Bloody Sunday it was preceded by a solemn commemoration of those that died a hundred years ago which I thought was beautifully done. Here’s a video tribute made by the GAA itself, played at the end of the pre-match commemoration along with specially-composed music.

After the match there was a wreath-laying ceremony involving the players which was unfortunately spoiled on the television broadcast by a commentator who talked all the way over it.

The match itself was a very one-sided affair, which was effectively all over by half time (when the score was Dublin 2-12 Meath 0-2). It ended Dublin 3-21 Meath 0-9, which is a margin of 21 points: quite a thrashing for Meath. I’m not an expert, but the Dublin side were far more mobile and inventive than Meath and thoroughly deserved their win.

There wasn’t a crowd of course. I think the commemorative event would have been even more emotional if there had been. Watching the actual match though it struck me that we’re all getting used to watching sport in an empty stadium. It’s probably going to take some getting used to the noise when (if) live audiences eventually return.

UPDATE: Tipperary beat Cork in Munster final this afternoon to win it for the first time in 85 years. The team were wearing replica jerseys of those worn by the Tipperary team that played Dublin in 1920.

After all the provincial finals, including a surprise win for Cavan over Donegal in Ulster, the four teams in the semi-finals of the All Ireland Senior Football Championship in 2020 is exactly the same as it was in 1920. The final, between Dublin and Tipperary, was not played until 1922.

(The match played on Bloody Sunday was a Challenge Match not part of the Championship.

Domhnach na Fola

Posted in History, Sport with tags , , , , , , , , , , , , on November 21, 2020 by telescoper

In the days before lockdown I would often travel past Croke Park on the train from Maynooth into Dublin Connolly station. It’s a magnificent stadium, with a capacity over 80,000, its stands towering up on all sides of the playing field which is used for major sporting events organized by the Gaelic Athletics Association (GAA), chiefly hurling and gaelic football. It’s located quite close to Drumcondra Station, the last stop before Connolly on the way into Dublin. I’ve never actually been inside the ground, and you can’t see much of the interior from the train because of the stands, but I do hope to see a match there one day.

Croke Park looked very different a hundred years ago today, on November 21st 1920 (which was a Sunday).

Croke Park, looking towards Hill 16, taken on the day of November 21st 1920.

Incidentally, the low hill you can see in the background is Hill 16. There’s a story that this was built up using rubble from buildings destroyed during the 1916 Easter Rising, but this seems to be apocryphal.

Anyway, as you can see, there wasn’t much in the way of buildings around the playing field in those days, and not much to give spectators cover if they were trying to flee from gunfire.

A Gaelic football match between Dublin and Tipperary started in Croke Park at 2.45 pm on November 21st. About ten minutes into the game, armed police (including members of the regular Royal Irish Constabulary, Auxiliaries, and some Black and Tans) suddenly arrived at the southern end of the park, panicking some of the spectators who tried to run away. Without warning the police opened fire on the crowd. The first to die was 11 year old William Robinson who was sitting in a tree outside the ground to get a better view. Overall the firing lasted about 90 seconds. Thirteen people were killed outright and another died of his wounds later. Others were injured either by gunfire or in the crush resulting from the panic.

Among the dead was Tipperary’s star player Michael Hogan, who was shot dead on the playing field as he tried to find cover. Information from post-mortems released many years after the event revealed that most of the victims had been shot in the back.

Michael Hogan, star player and Captain for the Tipperary team at Croke Park on Bloody Sunday. He died that day.

The massacre could have been even worse had the British forces at the other end of the ground, who had an armoured car with a machine gun, shown more restraint. The machine gun was fired above the heads of the people running towards this contingent. They didn’t shoot anyone but they did force the crowd back towards the gunfire from the other end of the ground. Had they opened fire at the crowd there would have been a massacre on the scale of Amritsar, where hundreds died.

Witnesses also said that while the security forces let all the Dublin players go, they lined up the entire Tipperary team against a fence and were preparing to shoot them all when a junior officer intervened and ordered them to be released. Tipperary was perceived to be a hotbed of IRA activity. Michael Hogan was in fact a member of the Irish Volunteers.

So what on Earth had happened to trigger this indiscriminate slaughter, on the day known now as Bloody Sunday (Irish: Domhnach na Fola)

The overall context is the Irish War of Independence which started in 1919 and was largely a guerilla campaign waged in rural areas. There had not been large-scale eruptions of violence in Dublin. That changed on November 21st 1920. That morning, members of the Irish Republican Army under the direction of Michael Collins, had carried out an operation across Dublin intended to eliminate the ability of the British forces to gather intelligence on the IRA. Hit squads entered the homes of known or suspected British intelligence operatives across the town and shot them. Fifteen people were killed that morning, including at least two innocent civilians in the process.

The IRA members responsible for the killings on Sunday morning melted away into the city. Once again the police and security services seemed to be fighting an invisible enemy. However, knowing that there was a football match going on that afternoon, and that at least some of those involved with the GAA had strong Republican leanings and may indeed be active IRA members, they decided to search all the spectators at the match of which there were over 10,000. The hope was, presumably, to find in the crowd at least some of those responsible for the morning’s assassinations. Instructions were given that anyone who ran away when the search operation began should be presumed guilty and shot.

News about the morning’s events had spread through Dublin that morning and it was widely anticipated that the British would carry out reprisal killings, probably in their usual indiscriminate fashion they had employed previously. When armed men arrived in vehicles outside the ground, the instinct of many spectators was therefore to run even before the searching began. Nervous and trigger-happy police deployed in a harebrained plan to make the slaughter inevitable. Nobody has ever been brought to justice for the murders at Croke Park.

Later that day two members of the IRA were caught by the security services, taken to Dublin Castle, beaten and then shot under the pretext that they were trying to escape. These killings brought the death toll past thirty. Bloody Sunday indeed.

The events in Croke Park handed a major propaganda victory to the IRA and also sparked an escalation of the violence. Just a week later, at Kilmichael in County Cork, the IRA ambushed two trucks carrying a total of 18 Auxiliaries, killing 17 of them and leaving the other for dead. On December 11th the British burned down a large part of the city of Cork in retaliation against another attack on their forces. And so it went on into 1921 to the point where the British eventually realized that Ireland had become ungovernable (by them) and a process was started that brought about independence (at least for part of Ireland).

As you can imagine there have been many commemorations of the grim events of a century ago. I watched a very interesting documentary on the TV earlier this week and there have been many articles in the newspapers and elsewhere about it, taking different angles. Those I found the most moving were those that dealt with the memory of the innocent lives lost. One very poignant idea was to stage 14 very short plays around Croke Park about each of the victims.

Here is a sort of trailer, featuring the heartbreaking story of Jane Boyle – the only woman to die on Bloody Sunday. Her death was particularly tragic as she was due to marry her fiancé Daniel Byron the following week. The couple went to mass at St Kevin’s Church on Harrington Street on Sunday morning and proceeded to Croke Park afterwards. When the firing started, they fled. In the scramble for safety, Daniel felt Jane’s hand go limp; she had been shot in the back and died instantly. She was buried later that week in her wedding gown.